(2aS)-2a,4,5,5aβ,6,6aβ,9bβ,9c-Octahydro-9,9cβ-dimethyl-2H-naphtho[1,8-bc:3,2-b']difuran-2,8(3H)-dione

(4R)-2-Oxo-3,4aβ-dimethyl-4α-hydroxy-2,4,4a,5,6,7,8,8aβ,9,9aβ-decahydronaphtho[2,3-b]furan-5β-carboxylic acid lactone